That is part of Webster's mod KM.
https://www.subsim.com/radioroom/dow...o=file&id=1017
The "Downloads" menu item is missing, but go to any of the mod threads with a download, and then you can work your way to the "Search" function. Must have been a site update that went wonky. Probably Windows 11... lol
As for the Japanese radar, initially the Yamato is the only ship with it, but as time passes, more and more get it. Same with the planes.
Edit: Say uh KM... we're both dunderheads... Instead of "Downloads", it now says "Mods"... same link though...